The invention provides a plug-in hybrid-electric-vehicle power assembly with better power matching property. A crankshaft of an engine is connected with a first clutch and a first sun wheel of a first planet row in sequence from left to right; a motor shaft of a driving motor penetrates through a second planet carrier of a second planet row from left to right and then is fixedly connected with a second sun wheel; a second gear and a fourth gear are fixedly arranged on a connecting shaft in parallel from left to right; the right end of the connecting shaft is connected with a transmission by a second clutch; a first gear and a third gear are respectively and fixedly connected with a first gear ring of the first planet row and a second planet carrier of the second planet row, and are respectively meshed with the second gear and the fourth gear; a first planet carrier of the first planet row and the second planet carrier of the second planet row are fixedly connected and are connected with a brake by an outer edge; and the first sun wheel of the first planet row is positioned in the first planet carrier, a first planet wheel is rotationally arranged on the first planet carrier, the first gear ring is positioned outside the first planet carrier and the second sun wheel of the second planet row is positioned in the second planet carrier.